1. Field of the Invention
The present invention relates to an optical transponder that receives a tributary signal such as an SDH/SONET signal, a GbE (Gigibit Ethernet) signal, and an SAN (Storage Area Network) signal in a WDM (Wavelength Division Multiplexing) transmission system and an SDH (Synchronous Digital Hierarchy)/SONET (Synchronous Optical Network) system, and more particularly, to an optical transponder having a switching function.
2. Description of the Related Art
An optical transponder interconnects a WDM transmission system and an SDH/SONET system with a client network. The optical transponder has been used to receive an SDH/SONET signal such as an STM-16/OC-48 signal, an STM-64/OC-192 signal, etc. Nowadays, the demand for a connection for various tributary signals such as a GbE signal, an FC (Fiber Channel) signal, an ESCON (Enterprise Systems CONnectivity) signal, etc., i.e., the demand for a multiprotocol signal processing, has increased due to an increase of data communication traffic.
As the transmission speed through an optical channel of the WDM transmission system has increased from 2.5 Gb/s to 10 Gb/s, four STM-16/OC-48 signals are multiplexed or a plurality of GbE signals are multiplexed as a 10 Gb/s OTN (OTU2) signal in order to effectively operate the optical channel of the WDM transmission system. To this end, an optical transponder is required.
A commercialized optical transponder receives up to eight channels of the GbE signal and multiplexes it as an OTU2 (Optical Channel Transport Unit for 10G) signal for transmission.
However, a conventional optical transponder does not have a switching function required for the GbE signal to change a transmission route of the signal with respect to each multiplexed channel (port). A signal that is input to an nth channel (port) must be output to the nth port at a remote side. Such a fixed operation causes inconvenience in that an operator has to change the transmission route personally when a network configuration needs a change in the transmission route. This operation takes a lot of time, thereby degrading the flexibility of network utilization.